Correlation Between Osseous Degenerative Changes on Cone Beam Computed Tomography and Disc Displacement on Magnetic Resonance Imaging in Temporomandibular Joint Osteoarthritis.

Abstract

<h4>Objective of work</h4>Osteoarthritis (OA) of the temporomandibular joint (TMJ) is a degenerative condition affecting both osseous and soft tissue structures. Cone beam computed tomography (CBCT) offers detailed visualization of osseous changes, while magnetic resonance imaging (MRI) provides superior assessment of soft tissues, particularly the articular disc. The relationship between bony degeneration and disc abnormalities remains poorly defined. This study examined the correlation between CBCT-identified osseous radiological features of TMJ OA and MRI-detected disc displacement patterns.<h4>Materials and methods</h4>A cross-sectional analysis was performed on 198 TMJs from 99 patients clinically diagnosed with TMJ OA, where both MRI and CBCT imaging were performed in the same patient to enable direct comparative analysis. MRI was used to classify disc position as normal, partial displacement with reduction, complete displacement with reduction (DDR), or complete displacement without reduction (DDWR). CBCT scans were assessed for degenerative bone changes, including subchondral cysts, erosions, generalized sclerosis, osteophytes, and loose calcified bodies. OA severity was graded using the Ahmad and Schiffman criteria. Statistical evaluation was conducted using Fisher's Exact Test.<h4>Results</h4>A statistically significant correlation was found between OA severity and disc displacement type (p < 0.001). DDWR was most frequently associated with Grade 2 OA (26.8%). Subchondral cysts (p = 0.004), erosions (p < 0.001), generalized sclerosis (p < 0.001), and osteophytes (p < 0.001) occurred with significantly higher prevalence in patients presenting with DDWR. Loose calcified bodies showed no significant association with disc position (p = 0.191).<h4>Conclusions</h4>There is an association between degenerative osseous changes and disc displacement patterns in TMJ OA, and DDWR represents a more advanced stage of internal derangement accompanied by pronounced bone remodeling. These results support the combined use of CBCT and MRI for the comprehensive assessment of TMJ OA.